/// <summary>
/// Verify that signature matches the data.
/// </summary>
/// <param name="signature">Generated signature.</param>
/// <param name="data">Data to valuate.</param>
/// <returns></returns>
public bool Verify(byte[] signature, byte[] data)
{
GXBigInteger msg;
if (PublicKey == null)
{
if (PrivateKey == null)
{
throw new ArgumentNullException("Invalid private key.");
}
PublicKey = PrivateKey.GetPublicKey();
}
if (PublicKey.Scheme == Ecc.P256)
{
using (SHA256 sha = new SHA256CryptoServiceProvider())
{
msg = new GXBigInteger(sha.ComputeHash(data));
}
}
else
{
using (SHA384 sha = new SHA384CryptoServiceProvider())
{
msg = new GXBigInteger(sha.ComputeHash(data));
}
}
GXByteBuffer pk = new GXByteBuffer(PublicKey.RawValue);
GXByteBuffer bb = new GXByteBuffer(signature);
int size = SchemeSize(PublicKey.Scheme);
GXBigInteger sigR = new GXBigInteger(bb.SubArray(0, size));
GXBigInteger sigS = new GXBigInteger(bb.SubArray(size, size));
GXBigInteger inv = sigS;
inv.Inv(curve.N);
// Calculate u1 and u2.
GXEccPoint u1 = new GXEccPoint(curve.G.x, curve.G.y, new GXBigInteger(1));
GXEccPoint u2 = new GXEccPoint(new GXBigInteger(pk.SubArray(1, size)),
new GXBigInteger(pk.SubArray(1 + size, size)), new GXBigInteger(1));
GXBigInteger n = msg;
n.Multiply(inv);
n.Mod(curve.N);
Multiply(u1, n, curve.N, curve.A, curve.P);
n = new GXBigInteger(sigR);
n.Multiply(inv);
n.Mod(curve.N);
Multiply(u2, n, curve.N, curve.A, curve.P);
u1.z = new GXBigInteger(1);
u2.z = new GXBigInteger(1);
JacobianAdd(u1, u2, curve.A, curve.P);
FromJacobian(u1, curve.P);
return(sigR.Compare(u1.x) == 0);
}
/// <summary>
/// Verify that signature matches the data.
/// </summary>
/// <param name="signature">Generated signature.</param>
/// <param name="data">Data to valuate.</param>
/// <returns></returns>
public bool Verify(byte[] signature, byte[] data)
{
GXBigInteger msg;
using (SHA256 sha = new SHA256CryptoServiceProvider())
{
msg = new GXBigInteger(sha.ComputeHash(data));
}
if (PublicKey == null)
{
PublicKey = PrivateKey.GetPublicKey();
}
GXByteBuffer pk = new GXByteBuffer(PublicKey.RawValue);
GXByteBuffer bb = new GXByteBuffer(signature);
GXBigInteger sigR = new GXBigInteger(bb.SubArray(0, 32));
GXBigInteger sigS = new GXBigInteger(bb.SubArray(32, 32));
GXBigInteger inv = sigS;
inv.Inv(curve.N);
// Calculate u1 and u2.
GXEccPoint u1 = new GXEccPoint(curve.G.x, curve.G.y, new GXBigInteger(1));
GXEccPoint u2 = new GXEccPoint(new GXBigInteger(pk.SubArray(1, 32)), new GXBigInteger(pk.SubArray(33, 32)), new GXBigInteger(1));
GXBigInteger n = msg;
n.Multiply(inv);
n.Mod(curve.N);
Multiply(u1, n, curve.N, curve.A, curve.P);
n = new GXBigInteger(sigR);
n.Multiply(inv);
n.Mod(curve.N);
Multiply(u2, n, curve.N, curve.A, curve.P);
// add = Math.add(u1, u2, P = curve.P, A = curve.A)
u1.z = new GXBigInteger(1);
u2.z = new GXBigInteger(1);
JacobianAdd(u1, u2, curve.A, curve.P);
FromJacobian(u1, curve.P);
return(sigR.Compare(u1.x) == 0);
}
/// <summary>
/// Sign given data using public and private key.
/// </summary>
/// <param name="data">Data to sign.</param>
/// <returns>Signature</returns>
public byte[] Sign(byte[] data)
{
if (PrivateKey == null)
{
throw new ArgumentException("Invalid private key.");
}
GXBigInteger msg;
using (SHA256 sha = new SHA256CryptoServiceProvider())
{
msg = new GXBigInteger(sha.ComputeHash(data));
}
GXBigInteger pk = new GXBigInteger(PrivateKey.RawValue);
GXEccPoint p;
GXBigInteger n = new GXBigInteger(10);
GXBigInteger r;
GXBigInteger s;
do
{
if (CustomRandomNumber != null)
{
n = CustomRandomNumber;
}
else
{
n = GetRandomNumber(PrivateKey.Scheme);
}
p = new GXEccPoint(curve.G.x, curve.G.y, new GXBigInteger(1));
Multiply(p, n, curve.N, curve.A, curve.P);
r = p.x;
r.Mod(curve.N);
n.Inv(curve.N);
//s
s = new GXBigInteger(r);
s.Multiply(pk);
s.Add(msg);
s.Multiply(n);
s.Mod(curve.N);
} while (r.IsZero || s.IsZero);
byte recoveryId;
if (p.y.IsOne)
{
recoveryId = 1;
}
else
{
recoveryId = 0;
}
if (p.y.Compare(curve.N) == 1)
{
recoveryId += 2;
}
GXByteBuffer signature = new GXByteBuffer();
signature.Set(r.ToArray());
signature.Set(s.ToArray());
return(signature.Array());
}
